The ACA employer mandate requires any business that averaged at least 50 full-time employees in the prior calendar year to offer affordable, minimum-value health insurance to at least 95% of its full-time workforce and their dependent children, or pay a per-employee penalty when a worker buys subsidized coverage on the Marketplace. For 2026, that penalty is either $3,340 or $5,010 per employee per year, depending on which part of the rule you fall short on. The threshold sounds simple. The counting method is where mid-size employers most often get caught out.
Does the Mandate Apply to Your Business
The mandate applies to Applicable Large Employers, meaning any business that averaged 50 or more full-time employees, including full-time equivalents, during the previous calendar year. A full-time employee is one who averages at least 30 hours of service per week or 130 hours in a calendar month.
Full-time equivalents are where the math gets interesting. Add up the monthly hours worked by everyone who was not full-time, cap each person at 120 hours, and divide the total by 120. That gives you your equivalent count for the month. Add it to your actual full-time head count, then average across all 12 months. If the annual average lands at 50 or higher, the mandate applies to you the following year.1Internal Revenue Service. Determining if an Employer is an Applicable Large Employer
Two rules commonly change the answer for businesses near the line.
First, aggregation. Companies under common ownership or common control are treated as a single employer for this count. Two entities with 30 full-time employees each are a single 60-employee Applicable Large Employer if they share common control, even though neither one on its own crosses 50.2Office of the Law Revision Counsel. 26 USC 4980H – Shared Responsibility for Employers Regarding Health Coverage
Second, the seasonal worker exception. If your workforce exceeded 50 full-time employees (counting equivalents) for 120 days or fewer during the year, and the workers pushing you over were seasonal, you are not treated as an Applicable Large Employer.1Internal Revenue Service. Determining if an Employer is an Applicable Large Employer Retailers who staff up only for the holidays are the classic beneficiaries.
What Counts as Qualifying Coverage
Offering insurance is not enough on its own. To satisfy the mandate, the coverage has to clear two tests, and it has to reach enough of your workforce.
Minimum Value
A plan provides minimum value if it is designed to pay for at least 60% of the total allowed costs of covered benefits. A plan below that actuarial threshold is treated the same as no qualifying coverage at all, no matter what employees pay for it.3Internal Revenue Service. Minimum Value and Affordability
Affordability
Affordability is measured against the employee’s required contribution for self-only coverage. For plan years beginning in 2026, coverage is affordable if the employee’s share does not exceed 9.96% of household income.4Internal Revenue Service. Revenue Procedure 2025-25 – Indexing Adjustments for Required Contribution Percentage for 2026 The percentage is indexed and changes annually, so it is worth confirming each fall when the IRS publishes the update.
Because employers rarely know an employee’s household income, the IRS provides three safe harbors. Passing any one of them shields you from the affordability penalty for that employee.
- W-2 safe harbor. The employee’s monthly contribution cannot exceed 9.96% of Box 1 W-2 wages divided by 12. It can only be applied after year-end because the final W-2 figure isn’t known until then.
- Rate-of-pay safe harbor. Multiply the employee’s lowest hourly rate by 130 (or use monthly salary for salaried staff). The employee contribution cannot exceed 9.96% of that. This one works prospectively, which is why planners tend to lean on it.
- Federal poverty line safe harbor. The employee’s monthly contribution cannot exceed 9.96% of the single-person federal poverty level divided by 12. For 2026, the mainland poverty level of $15,960 caps the monthly employee contribution at roughly $132.47.5Department of Health and Human Services. 2026 Poverty Guidelines – 48 Contiguous States
The 95% Rule and Dependents
Qualifying coverage has to be offered to at least 95% of your full-time employees and their dependents. Dependents means children up to age 26. Spouses are not part of the dependent requirement, though employers commonly offer spousal coverage anyway.3Internal Revenue Service. Minimum Value and Affordability
The Penalties and What Triggers Them
The penalties only apply when at least one full-time employee actually receives a premium tax credit for coverage bought on the Marketplace. No subsidized employee, no penalty, even when coverage is inadequate. For any employer with dozens of full-timers, though, it is safe to assume at least one will end up on the Marketplace if the offer is missing or too expensive.6Internal Revenue Service. Questions and Answers on Employer Shared Responsibility Provisions Under the Affordable Care Act
The 4980H(a) Penalty: Failure to Offer Coverage
If you fail to offer coverage to at least 95% of full-time employees and any one of them gets a Marketplace subsidy, the penalty applies across nearly your entire full-time workforce. For 2026, it is $3,340 per full-time employee per year, minus the first 30 employees. A company with 100 full-time workers would owe $3,340 × 70 = $233,800 for the year.7Internal Revenue Service. Revenue Procedure 2025-26 – Indexing Adjustments for Section 4980H This is the harsher penalty because it hits the whole workforce, not just the workers who got subsidies.
The 4980H(b) Penalty: Coverage Offered but Inadequate
If you do offer coverage to 95% or more of your full-time workforce but the plan fails minimum value or affordability for a particular employee, and that employee receives a subsidy, the penalty is $5,010 per subsidized employee for 2026. It applies only to each employee who actually took a premium tax credit, not the workforce as a whole.7Internal Revenue Service. Revenue Procedure 2025-26 – Indexing Adjustments for Section 4980H Its monthly total is capped at what the (a) penalty would have been for that month.
Neither penalty is tax-deductible. Section 4980H explicitly cross-references the deduction denial in Section 275(a)(6).2Office of the Law Revision Counsel. 26 USC 4980H – Shared Responsibility for Employers Regarding Health Coverage
Annual Reporting on Forms 1094-C and 1095-C
Every Applicable Large Employer files two IRS forms each year to document what coverage was offered, to whom, and at what cost. Reporting failures carry their own penalties, separate from the coverage penalties.
Form 1095-C is the employee-level document. One goes to each full-time employee, showing the months coverage was offered, the lowest cost of self-only coverage, and a series of indicator codes describing what was offered and which safe harbor (if any) applied.8Internal Revenue Service. Instructions for Forms 1094-C and 1095-C Form 1094-C is the employer-level transmittal that summarizes head counts and confirms whether the 95% offer bar was met.
For the 2025 calendar year, employee statements must be furnished by March 2, 2026. Paper filings with the IRS are also due March 2, 2026; electronic filings are due March 31, 2026. Any employer filing 10 or more information returns must file electronically through the ACA Information Returns (AIR) system,9Internal Revenue Service. Affordable Care Act Information Returns (AIR) which effectively covers every Applicable Large Employer.
Late or incorrect filings for returns due in 2026 draw the following per-form penalties:
- Up to 30 days late: $60 per form.
- 31 days late through August 1: $130 per form.
- After August 1 or not filed at all: $340 per form.
- Intentional disregard: $680 per form.
Those amounts apply separately for failing to file with the IRS and for failing to furnish statements to employees, so an employer who does both wrong on the same form pays twice.10Internal Revenue Service. Information Return Penalties For a 200-employee company that misses the deadline entirely: $340 × 200 × 2 = $136,000.
If the IRS Says You Owe: Letter 226J
The IRS does not send a bill for the coverage penalty. It sends Letter 226J, which is a proposed assessment. The letter states the proposed Employer Shared Responsibility Payment and includes Form 14765, listing the employees whose subsidies drove the calculation.11Internal Revenue Service. Understanding Your Letter 226-J
You respond on Form 14764, agreeing or disagreeing. A disagreement has to point to specific errors on the employee listing. Common defenses include showing that coverage was in fact offered but miscoded on the 1095-C, or that an employee flagged as full-time was not. The response deadline is printed on the letter, so read yours carefully.
If the IRS does not accept your response, you can request a conference with the Office of Appeals. Proposed amounts of $25,000 or less per tax period can use the simplified request on Form 12203; larger amounts require a formal written protest.12Internal Revenue Service. Preparing a Request for Appeals What decides these fights is the quality of the underlying 1094-C and 1095-C records. Careless coding at filing time rarely produces the documentation needed to win on appeal.